Markdown and a sensible directory structure has been working great for me. Put it somewhere synced to all the devices, and it's the quickest and easiest form to

Markdown and a sensible directory structure has been working great for me. Put it somewhere synced to all the devices, and it's the quickest and easiest form to read and write anywhere. If I really need a nicely formatted copy I can produce one easily, but this is rare. In the right editor syntax highlighting makes the structure obvious, and automatic formatting/linting keeps things sensible. Any requirement for multimedia has been satisfied with links to local files or online sources. The only issue has been collaboration, but in my experience it's easier to just use whatever my collaborators prefer. I can still have my own markdown as a searchable and familiar origin point, with links into whatever they are using.